Here is the rear section in place. Then you go along and screw the floor into the wooden support down the middle and go along the edges and screw the floor into the ribs of the boat itself. Make sure you use screws short enough so they don't go thru the skin of the boat.
Sorry I had to say that. Use a washer so you don't go thru the wood floor. Very simple. Use cardboard to lay it out before you cut the wood.